Light emitting device

ABSTRACT

Alight emitting device includes a substrate including a base member including a front surface, a rear surface opposite to the front surface, a bottom surface perpendicular to the front surface, and a top surface opposite to the bottom surface, a first wiring portion located on the front surface, and a second wiring portion located on the rear surface; a light emitting element electrically connected with the first wiring portion; and a first reflective member covering a lateral surface of the light emitting element and the front surface of the base member. The base member has a recessed portion opened on the rear surface and the bottom surface. The substrate includes a third wiring portion covering an inner wall of the recessed portion and electrically connected with the second wiring portion, and a via in contact with the first wiring portion, the second wiring portion and the third wiring portion.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation application of U.S. patent application Ser. No.16/229,666, filed Dec. 21, 2018, which claims priority to JapanesePatent Application No. 2017-246556, filed on Dec. 22, 2017, JapanesePatent Application No. 2018-005345, filed on Jan. 17, 2018, JapanesePatent Application No. 2018-115073, filed on Jun. 18, 2018, and JapanesePatent Application No. 2018-139908, filed on Jul. 26, 2018, thedisclosures of which are hereby incorporated by reference in theirentireties.

BACKGROUND

The present disclosure relates to a light emitting device.

Alight emitting device including a concave-shaped electrode electricallyconnected with an electrode pattern via a through-hole is known. Theconcave-shaped electrode of such a light emitting device is electricallyconnected with an electrode of a motherboard with a solder, and thus thelight emitting device is mounted on the motherboard (see, for example,Japanese Patent Publication No. 2012-124191).

SUMMARY

Light emitting elements (LED elements) are increased in output level,and accordingly, heat generated from the light emitting elements isincreased. In such a situation, a light emitting device with improvedheat dissipation is now desired. Certain non-limiting and exemplaryembodiment herein provides a light emitting device with improved heatdissipation.

A light emitting device in certain embodiment according to the presentdisclosure includes a substrate, a light emitting element, and a firstreflective member. The substrate includes a base member, a first wiringportion, a second wiring portion, and a third wiring portion. The basemember includes a front surface extending in a first direction as alonger direction and a second direction as a shorter direction, a rearsurface located opposite to the front surface, a bottom surface adjacentto and perpendicular to the front surface, and a top surface locatedopposite to the bottom surface. The first wiring portion is located onthe front surface, and the second wiring portion is located on the rearsurface. The light emitting element is electrically connected with thefirst wiring portion and placed on the first wiring portion. The firstreflective member covers a lateral surface of the light emitting elementand the front surface of the base member. The base member has a recessedportion opened on the rear surface and the bottom surface. The thirdwiring portion covers an inner wall of the recessed portion, and iselectrically connected with the second wiring portion. The base memberhas a via in contact with the first wiring portion, the second wiringportion, and the third wiring portion.

According to the above aspect, it is possible to provide a lightemitting device with improved heat dissipation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic perspective view of a light emitting deviceaccording to embodiment 1 of the present disclosure.

FIG. 1B is a schematic perspective view of the light emitting deviceaccording to embodiment 1.

FIG. 1C is a schematic front view of the light emitting device accordingto embodiment 1.

FIG. 2A is a schematic cross-sectional view of the light emitting devicetaken along line 2A-2A in FIG. 1C.

FIG. 2B is a schematic cross-sectional view of the light emitting devicetaken along line 2B-2B in FIG. 1C.

FIG. 3 is a schematic rear view of the light emitting element accordingto embodiment 1.

FIG. 4A is a schematic perspective view of a base member, vias and athird wiring portion according to embodiment 1.

FIG. 4B is a schematic perspective view of the base member, the vias andthe third wiring portion according to embodiment 1.

FIG. 4C is a schematic perspective view of the base member, the vias andthe third wiring portion according to embodiment 1.

FIG. 5 is a schematic bottom view of the light emitting device accordingto embodiment 1.

FIG. 6A is a schematic cross-sectional view of the light emitting deviceaccording to embodiment 1, also showing an enlarged view of a portionenclosed by the dashed line.

FIG. 6B is a schematic cross-sectional view of a light emitting deviceaccording to a modification of embodiment 1, also showing an enlargedview of a portion enclosed by the dashed line.

FIG. 7A is a schematic front view of a substrate according to embodiment1.

FIG. 7B is a schematic front view of a substrate according to anothermodification of embodiment 1.

FIG. 7C is a schematic front view of a substrate according to amodification of embodiment 1.

FIG. 8 is a schematic right side view of the light emitting deviceaccording to embodiment 1.

FIG. 9A is a schematic perspective view of a light emitting deviceaccording to embodiment 2.

FIG. 9B is a schematic perspective view of the light emitting deviceaccording to embodiment 2.

FIG. 9C is a schematic front view of the light emitting device accordingto embodiment 2.

FIG. 9D is a schematic bottom view of the light emitting deviceaccording to embodiment 2.

FIG. 10 is a schematic cross-sectional view of the light emitting devicetaken along line 10A-10A in FIG. 9C.

FIG. 11 is a schematic rear view of the light emitting device accordingto embodiment 2.

FIG. 12A is a schematic perspective view of a light emitting deviceaccording to a modification of embodiment 2.

FIG. 12B is a schematic cross-sectional view of the light emittingdevice according to the modification of embodiment 2.

FIG. 12C is a schematic cross-sectional view of a light emitting deviceaccording to another modification of embodiment 2.

FIG. 12D is a schematic rear view of the light emitting device accordingto said another modification of embodiment 2.

FIG. 12E is a schematic cross-sectional view of a light emitting deviceaccording to still another modification of embodiment 2.

FIG. 12F is a schematic cross-sectional view of a light emitting deviceaccording to yet another modification of embodiment 2.

FIG. 12G is yet another schematic cross-sectional view of a lightemitting device according to a modification of embodiment 2.

FIG. 12H is yet another schematic cross-sectional view of a lightemitting device according to a modification of embodiment 2.

FIG. 12I is yet another schematic cross-sectional view of a lightemitting device according to a modification of embodiment 2.

FIG. 12J is a schematic cross-sectional view of a light emitting deviceaccording to yet another modification of embodiment 2.

FIG. 12K is a schematic front view of a substrate according toembodiment 2.

FIG. 13A is a schematic perspective view of a light emitting deviceaccording to embodiment 3.

FIG. 13B is a schematic perspective view of the light emitting deviceaccording to embodiment 3.

FIG. 13C is a schematic front view of the light emitting deviceaccording to embodiment 3.

FIG. 14A is a schematic cross-sectional view of the light emittingdevice taken along line 14A-14A in FIG. 13C.

FIG. 14B is a schematic cross-sectional view of a light emitting deviceaccording to a modification of embodiment 3.

FIG. 14C is a schematic cross-sectional view of a light emitting deviceaccording to a modification of embodiment 3.

FIG. 15 is a schematic rear view of the light emitting device accordingto embodiment 3.

FIG. 16 is a schematic bottom view of the light emitting deviceaccording to embodiment 3.

FIG. 17A is a schematic front view of a substrate, a first lightemitting element, a second light emitting element and a third lightemitting element according to embodiment 3.

FIG. 17B is a schematic front view of a substrate, a first lightemitting element, a second light emitting element and a third lightemitting element according to a modification of embodiment 3.

FIG. 17C is a schematic front view of a substrate, a first lightemitting element, a second light emitting element and a third lightemitting element according to a modification of embodiment 3.

FIG. 18A is a schematic cross-sectional view of a light emitting deviceaccording to a modification of embodiment 3.

FIG. 18B is a schematic cross-sectional view of a light emitting deviceaccording to a modification of embodiment 3.

FIG. 19 is a schematic cross-sectional view of a light emitting deviceaccording to embodiment 4.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be describedwith reference to the drawings when necessary. Light emitting devicesdescribed below embody the technological idea of the present invention,and the present invention is not limited to any of the followingembodiments unless otherwise specified. A content described in oneembodiment is applicable to other embodiments and modifications. In thedrawings, the size, positional relationship or the like may beemphasized for clear illustration.

Embodiment 1

A light emitting device 1000 in embodiment 1 according to the presentdisclosure will be described with reference to FIG. 1A through FIG. 8.The light emitting device 1000 includes a substrate 10, at least onelight emitting element 20, and a first reflective member 40. Thesubstrate 10 includes a base member 11, at least one first wiringportion 12, at least one second wiring portion 13, at least one thirdwiring portion 14, and at least one via 15. The base member 11 includesa front surface 111 extending in a first direction, which is a longerdirection, and a second direction, which is a shorter direction, a rearsurface 112 located opposite to the front surface 111, a bottom surface113 adjacent to, and perpendicular to, the front surface 111, and a topsurface 114 located opposite to the bottom surface 113. In this example,as shown in e.g., FIG. 1C, the first direction coincides an X directionand the second direction coincides a Y direction. The base member 11includes at least one recessed portion 16. The first wiring portions 12are located on the front surface 111 of the base member 11. The secondwiring portion 13 is located on the rear surface 112 of the base member11. The light emitting element 20 is electrically connected with thefirst wiring portions 12 and is located on the first wiring portions 12.The first reflective member 40 covers a lateral surface 202 of the lightemitting element 20 and the front surface 111 of the base member 11. Theat least one recessed portion 16 is opened at the rear surface 112 andthe bottom surface 113. The third wiring portion 14 covers an inner wallof the recessed portion 16, and is electrically connected with thesecond wiring portion 13. The via 15 is in contact with the first wiringportion 12, the second wiring portion 13 and the third wiring portion14. The via 15 electrically connects the first wiring portion 12, thesecond wiring portion 13 and the third wiring portion 14 to each other.The via 15 runs through the base member 11 from the front surface 111 tothe rear surface 112. In this specification, the term “perpendicular”indicates that a tolerance of ±3 degrees from 90 degrees is allowed.

The via 15 may be in contact with the first wiring portion 12, thesecond wiring portion 13 and the third wiring portion 14. With such astructure, heat from the light emitting element 20 is transmitted to thesecond wiring portion 13 and/or the third wiring portion 14 through thevia 15, and whereby heat dissipation of the light emitting device 1000can be improved. In the case where the via 15 is in contact with thesecond wiring portion 13 and the third wiring portion 14, as shown inFIG. 3, the via 15 overlaps the second wiring portion 13 and the thirdwiring portion 14 as seen in a rear view. In the case where thesubstrate 10 has a plurality of the vias 15, all the plurality of vias15 may each be in contact with the first wiring portion 12, the secondwiring portion 13 and the third wiring portion 14. Alternatively, allthe plurality of vias 15 do not need to be in contact with the firstwiring portion 12, the second wiring portion 13 and the third wiringportion 14. In the case where, for example, the substrate 10 has theplurality of vias 15, one of the vias 15 may be in contact with one ofthe first wiring portions 12, one of the second wiring portions 13 andone of the third wiring portions 14 whereas another of the vias 15 maybe in contact with another one of the first wiring portions 12 andanother one of the second wiring portions 13 but out of contact withanother one of the third wiring portions 14. A part of the plurality ofvias 15 may be in contact with the first wiring portion 12, the secondwiring portion 13 and the third wiring portion 14, so that heatdissipation of the light emitting device 1000 can be improved. The via15 is preferably circular as seen in a rear view. With such a structure,the via 15 is easily formed by drilling or the like. In the case wherethe via 15 is circular as seen in a rear view, the via 15 preferably hasa diameter of 100 μm or greater and 150 μm or smaller. The structure inwhich the diameter of the via 15 is 100 μm or greater can improve heatdissipation of the light emitting device 1000. The structure in whichthe diameter of the via 15 is 150 μm or smaller can mitigate a decreasein the strength of the substrate 10. In this specification, the term“circle” encompasses a true circle and also a shape close to circle(e.g., an ellipse and a quadrangle with four rounded corners). It ispreferable that as seen in a rear view, an area size of the via 15overlapping the second wiring portion 13 is larger than an area size ofthe via 15 overlapping the third wiring portion 14. Such a structure canincrease the volumetric capacity of the via 15, and thus can improveheat dissipation of the light emitting device 1000. It is preferablethat the via 15 is located at the center of the substrate 10 in a Ydirection for the following reason. A portion of the base member 11 froman end of the via 15 to an end of the base member 11 in the Y directionis thinner than the rest of the area of the base member 11. However, inthe case where the via 15 is formed at the center of the base member 11in the Y direction, an area size of such a thinner portion is decreased.This can increase the strength of the base member 11.

As shown in FIG. 4A through FIG. 4C, the via 15 includes a portion D1,which extends in a direction from the rear surface 112 to the frontsurface 111 (i.e., Z direction) and in which the via 15 partiallyoverlaps with the third wiring portion 14 as seen from the rear surface.With such a structure, the via 15 and the third wiring portion 14 are incontact with each other in the X direction and the Y direction as wellas in the Z direction (i.e., direction from the rear surface 112 to thefront surface 111). This can increase the contact area size of the via15 and the third wiring portion 14. With such a structure, the heat fromthe light emitting element 20 is easily transmitted from the firstwiring portion 12 to the third wiring portion 14 through the via 15, andthus heat dissipation of the light emitting device 1000 can be improved.

The light emitting device 1000 maybe secured to a mounting substratewith a joining member such as a solder member or the like formed in therecessed portion 16. The third line 14 covering the inner wall of therecessed portion 16 may undesirably be subject to a force caused bythermal expansion of the joining member, or the like. With the via 15including the portion D1, which extends in the Z direction and in whichthe via 15 and the third wiring portion 14 are in contact with eachother, the joining strength between the via 15 and the third wiringportion 14 can be increased. Accordingly, the third wiring portion 14 isless likely to delaminate from the base member 11 even if the forcecaused by the joining member or the like due to thermal expansion isapplied to the third wiring portion 14.

The via 15 may include a conductive member which fills a through-holeformed in the base member 11. Alternatively, as shown in FIG. 2A, thevia 15 may include a fourth wiring 151 covering an inner surface of thethrough-hole in the base member 11 and a filling member 152 filling aspace enclosed by the fourth wiring 151. The filling member 152 may beconductive or insulating. The filling member 152 is preferably formed ofa resin material. In general, a pre-cured resin material has a higherfluidity than that of a pre-cured metal material, and therefore, easilyfills the space enclosed by the fourth wiring 151. Such use of a resinmaterial for the filling member 152 can make it easier to form thesubstrate 10. A resin material that easily fills the space enclosed bythe fourth wiring 151 may be, for example, an epoxy resin. In the casewhere a resin material is used for the filling member 152, the resinmaterial preferably contains at least one additive in order to decreasea linear thermal expansion coefficient. Such a manner can decrease thedifference in the linear thermal expansion coefficients between thefilling member 152 and the fourth wiring 151, and thus a gap, whichmight be generated by the heat from the light emitting element, is lesslikely to be formed between the fourth wiring 151 and the filling member152. The additive to be contained may be, for example, silicon oxide. Inthe case where the filling member 152 is formed of a material comprisinga metal, the heat dissipation can be improved. In the case where the via15 includes a conductive member filling the through-hole formed in thebase member 11, it is preferable that the conductive member is formed ofmaterial comprising a metal having a high heat conductivity such as Ag,Cu or the like.

The substrate 10 may have one recessed portion 16, or a plurality of therecessed portions 16. In the case where the substrate 10 has theplurality of recessed portions 16, the joining strength between thelight emitting device 1000 and the mounting substrate can be increased.The recessed portion 16 has a depth W3 defined from the rear surface 112to the front surface 111 on the bottom surface 113 side, and a depth W4defined from the rear surface 112 to the front surface 111 on the topsurface 114 side. The depths on the top surface 114 side and the bottomsurface 113 side may be equal, or may be deeper on the bottom surface113 side than on the top surface 114 side. In the case where as shown inFIG. 2B, the recessed portion 16 is deeper in the Z direction on thebottom surface 113 side than on the top surface 114 side, thickness W1of a portion of the base member 11 that is located on the top surface114 side with respect to the recessed portion 16 is greater thanthickness W2 of a portion of the base member 11 that is located on thebottom surface 113 side with respect to the recessed portion 16. Thiscan mitigate a decrease in the strength of the base member. In addition,depth W3 of the recessed portion 16 on the bottom surface 113 side isgreater than depth W4 of the recessed portion 16 on the top surface 114side. This can increase the volume of the joining member formed in therecessed portion 16. Therefore, the joining strength between the lightemitting device 1000 and the mounting substrate can be enhanced. Thelight emitting device 1000 may be either of a top view type, in whichthe rear surface 112 of the base member 11 and the mounting substrateface each other, or of a side view type, in which the bottom surface 113of the base member 11 and the mounting substrate face each other. Ineither case, the increase in the volume of the joining member canenhance the joining strength between the light emitting device 1000 andthe mounting substrate.

The joining strength between the light emitting device 1000 and themounting substrate can be increased especially in the case where thelight emitting device 1000 is employed as the side view type. Becausethe recessed portion 16 is deeper in the Z direction on the bottomsurface 113 side than on the top surface 114 side, the surface area sizeof the opening of the recessed portion 16 at the bottom surface 113 cabbe large. Because the surface area size of the opening of the recessedportion 16 is large at the bottom surface 113, which faces the mountingsubstrate, the surface area size of the joining member located on thebottom surface 113 can also be large. In this manner, the surface areasize of the joining member located on the surface facing the mountingsubstrate can be increased. This can increase the joining strengthbetween the light emitting device 1000 and the mounting substrate.

It is preferred that the maximum depth of the recessed portion 16 in theZ direction is 0.4 to 0.9 times the thickness of the base member 11 inthe Z direction. With the structure in which the depth of the recessedportion 16 is equal to or larger than 0.4 times the thickness of thebase member 11, the volume of the joining member formed in the recessedportion 16 can be increased. This can increase the joining strengthbetween the light emitting device 1000 and the mounting substrate. Withthe structure in which the depth of the recessed portion 16 is equal toor smaller than 0.9 times the thickness of the base member 11, thestrength of the base member is less likely to be decreased.

As shown in FIG. 2B, it is preferable that the recessed portion 16includes a parallel portion 161 extending from the rear surface 112 in adirection parallel to the bottom surface 113 (in the Z direction). Theprovision of the parallel portion 161 can increase the area size of theportion D1 (FIGS. 4A through 4C), which extends in the Z direction andin which the via 15 and the third wiring portion 14 are in contact witheach other. This improves the level of heat dissipation of the lightemitting device 1000. The provision of the parallel portion 161 can alsoincrease the volume of the recessed portion 16 even if the surface areasize of the opening of the recessed portion 16 at the rear surface 112is the same as in the case where the parallel portion 161 is notprovided. Such an increased volumetric capacity of the recessed portion16 can increase the amount of the joining member (e.g., a solder memberor the like) to be supplied in the recessed portion 16. Accordingly, thejoining strength can be enhanced between the light emitting device 1000and the mounting substrate. In this specification, the term “parallel”indicates that a tolerance of about ±3 degrees is allowed. As seen in across-sectional view, the recessed portion 16 includes an incliningportion 162 inclining so as to increase the thickness of the base member11 from the bottom surface 113. The inclining portion 162 may be definedby a straight line or a curved line.

It is preferred that the recessed portion 16 has a maximum height in theY direction that is 0.3 times to 0.75 times the thickness of the basemember 11 in the Y direction. With the structure in which the length ofthe recessed portion 16 in the Y direction is equal to or larger than0.3 times the thickness of the base member 11 in the Y direction, thevolume of the joining member formed in the recessed portion 16 can beincreased. This can increase the joining strength between the lightemitting device 1000 and the mounting substrate. With the structure inwhich the length of the recessed portion 16 in the Y direction is equalto or smaller than 0.75 times the thickness of the base member 11 in theY direction, the strength of the base member 11 is less likely to bedecreased.

As shown in FIG. 3, it is preferable that the recessed portion 16 isgenerally semicircular at the rear surface 112. Because the recessedportion 16 at the rear surface 112 is semicircular with no angularportion, a stress is less likely to concentrate to a particular positionof the recessed portion. Accordingly, the base member is less likely tobe broken. In this specification, the term “semicircle” encompasses atrue semicircle and also a shape close thereto (e.g., an semi-ellipse).

As shown in FIG. 3, in the case where there are the plurality ofrecessed portions 16 at the rear surface 112, it is preferable that theplurality of recessed portions 16 are located in a left-rightsymmetrical manner with respect to a center line 3C, of the base member11, parallel to the second direction (i.e., Y direction). With such astructure, when the light emitting device 1000 is mounted on themounting substrate with the joining member, a self-alignment effect iseffectively provided to mount the light emitting device 1000 in apredetermined mounting range with high precision.

At the bottom surface 113, the recessed portion 16 may have a generallyconstant depth in the Z direction, or the depth may be different betweenin a central portion and an end portion in the recessed portion 16. Itis preferable that as shown in FIG. 5, at the bottom surface 113, depthD2 of the central portion of the recessed portion 16 is the maximumdepth of the recessed portion 16 in the Z direction. With such astructure, at the bottom surface 113, thickness D3 of the base member 11in the Z direction can be larger at an end of the recessed portion 16 inthe X direction. This can increase the strength of the base member 11.In this specification, the term “central” indicates that a tolerance ofabout 5 μm is allowed. The recessed portion 16 may be formed by a knownmethod such as drilling, laser processing or the like.

As shown in FIG. 5, it is preferable that a portion of the first wiringportion 12 exposed to an outer lateral surface of the light emittingdevice 1000, more specifically, an outer lateral surface of the firstreflective member 40, is located either to the left of, or to the rightof, a center line 5C, of the base member 11, parallel to Z direction.With such a structure, the polarity of the light emitting device 1000can be recognized based on the position of that portion of the firstwiring portion 12. Alternatively, the first wiring portions 12 may havetwo portions which are exposed to the outer lateral surface of the lightemitting device 1000, and those two portions may be located each to theleft of, and to the right of, the center line 5C. In this case, it ispreferable that the one located to the left of the center line 5C andthe other located to the right of the center line 5C have differentshapes from each other on the outer lateral surface of the lightemitting device 1000, more specifically, the outer lateral surface ofthe first reflective member 40. With such a structure, the polarity ofthe light emitting device 1000 can be recognized based on the shape ofthe first wiring portion 12 on each of the above-described positions onthe outer lateral surface of the light emitting device 1000.

As shown in FIG. 6A, the first wiring portion 12, the second wiringportion 13 and/or the third wiring portion 14 may each include a wiringmain portion 12A and a plating portion 12B formed on the wiring mainportion 12A. In this specification, the term “wiring” refers to thefirst wiring portion 12, the second wiring portion 13 and/or the thirdwiring portion 14. The wiring main portion 12A may be formed of at leastone known material such as copper or the like. The provision of theplating portion 12B on the wiring main portion 12A can increase thereflectance of a surface of each wiring or can mitigate sulfurization ofwiring. For example, a phosphorus-containing nickel plating portion 120Amay be included in the plating portion 12B as a portion provided on thewiring main portion 12A. Nickel that contains phosphorus has anincreased hardness. Therefore, the provision of thephosphorus-containing nickel plating portion 120A on the wiring mainportion 12A can increase the hardness of the wiring. Accordingly, burris less likely to be generated on the wiring when the wiring is cut inorder to, for example, singulate the light emitting devices intoindividual pieces. The phosphorus-containing nickel plating portion 120Amay be formed by electrolytic plating or electroless plating.

As shown in FIG. 6A, it is preferable that the plating portion 12Bincludes a gold plating portion 120B at an outermost surface thereof.The provision of the gold plating portion 120B at the outermost surfaceof the plating portion 12B can mitigate oxidation and corrosion of thesurface of the first wiring portion 12, the second wiring portion 13and/or the third wiring portion 14, and thus provides a highsolderability. This can also increase the reflectance of the surface ofeach wiring or mitigate sulfurization of the wiring. It is preferablethat the gold plating portion 120B located at the outermost surface ofthe plating portion 12B is formed by electrolytic plating. By employingthe electrolytic plating, the amount of catalyst poison such as sulfuror the like can be smaller than in the case where the electrolessplating is employed. An addition reaction type silicone resin formed byusing a platinum-based catalyst may be cured while being in contact withthe gold plating portion 120B. In this case, the gold plating portion120B, when being formed by electrolytic plating, contains little sulfurand thus can mitigate reaction of sulfur and platinum. This can mitigatean insufficient curing of the addition reaction type silicone resinformed by using a platinum-based catalyst. In the case where the goldplating portion 120B is formed in contact with the phosphorus-containingnickel plating portion 120A, it is preferable that thephosphorus-containing nickel plating portion 120A and the gold platingportion 120B are formed by electrolytic plating. The different types ofplating portions may be formed by the same plating method, so that theproduction cost of the light emitting device 1000 can be reduced. The“nickel plating portion” may contain any other material as long ascontaining nickel. The “gold plating portion” may contain any othermaterial as long as containing gold.

It is preferable that the phosphorus-containing nickel plating portion120A is thicker than the gold plating portion 120B. With the structurein which the phosphorus-containing nickel plating portion 120A isthicker than the gold plating portion 120B, the hardness of the firstwiring portion 12, the second wiring portion 13 and/or the third wiringportion 14 can be easily increased. The thickness of thephosphorus-containing nickel plating portion 120A is preferably in therange of from at least 5 times to at most 500 times the thickness of thegold plating portion 120B, and more preferably in the range of from atleast 10 times to at most 100 times the thickness of the gold platingportion 120B.

As in a light emitting device 1000A shown in FIG. 6B, the platingportion 12B formed on the wiring main portion 12A of wiring may includea phosphorus-containing nickel plating portion 120C, a palladium platingportion 120D, a first gold plating portion 120E and a second goldplating portion 120F as layered structure. In the case where, forexample, the wiring main portion 12A is formed of copper, the layers ofthe phosphorus-containing nickel plating portion 120C, the palladiumplating portion 120D, the first gold plating portion 120E and the secondgold plating portion 120F can mitigate diffusion of copper in theplating portion 12B. This can mitigate a decrease in the adhesivenessbetween the layers of plating. The phosphorus-containing nickel platingportion 120C, the palladium plating portion 120D and the first goldplating portion 120E may be formed by electroless plating on the wiringmain portion 12A, whereas the second gold plating portion 120F may beformed by electrolytic plating. The second gold plating portion 120Fformed by electrolytic plating may be located at the outermost surface,thereby mitigating an insufficient curing of the addition reaction typesilicone resin formed by using a platinum-based catalyst.

As shown in FIG. 2A, the light emitting element 20 includes a mountingsurface facing the substrate 10 and a light extraction surface 201located opposite to the mounting surface. The light emitting element 20includes at least a semiconductor layered body 23, and positive andnegative electrodes 21 and 22 are provided on the semiconductor layeredbody 23. It is preferable that the positive and negative electrodes 21and 22 are formed on/above the same surface of the light emittingelement 20, and that the light emitting element 20 is flip-chip-mountedon the substrate 10. Such a structure does not require a wire thatsupplies electricity to the positive and negative electrodes 21 and 22of the light emitting element 20, and thus can decrease the size of thelight emitting device 1000. In the case where the light emitting element20 is flip-chip-mounted, the light extraction surface 201 is opposite toan electrode formation surface 203, on which the positive and negativeelectrodes 21 and 22 are located. In this specification, the lightemitting element 20 includes an element substrate 24, but the elementsubstrate 24 may be absent. In the case where the light emitting element20 is flip-chip-mounted on the substrate 10, the positive and negativeelectrodes 21 and 22 of the light emitting element 20 are connected withthe first wiring portion 12 via a conductive bonding member 60.

As shown in FIG. 2A and FIG. 7A, in the case where the light emittingelement 20 is flip-chip-mounted on the substrate 10, it is preferablethat the first wiring portion 12 includes at least one protrusion 121 atpositions each overlapping the positive and negative electrodes 21 and22 of the light emitting element 20 as seen in a front view. With thestructure in which the first wiring portions 12 each include theprotrusion 121, when the first wiring portions 12 are connected with theelectrodes 21 and 22 of the light emitting element 20 via the conductivebonding member 60, the positional alignment between the light emittingelement 20 and the substrate 10 is easily realized by a self-alignmenteffect.

As shown in FIG. 7B, one or both of the first wiring portions 12 mayinclude a wiring extending portion 123 extending in the X direction asseen in a front view. Alternatively, as shown in FIG. 7C, the firstwiring portions 12 do not need to include the wiring extending portion123 extending in the X direction as seen in a front view. The term“wiring extending portion” refers to a portion that is narrower, as seenin a front view, than the rest of the first wiring portions 12overlapping the light emitting element 20 and extends from the rest ofthe first wiring portions 12 overlapping the light emitting element 20.In the case where the wiring extending portion extends in the Xdirection, the “width of the wiring extending portion” refers to thesize of the wiring extending portion in the Y direction and the “widthof the part of the first wiring portion 12 overlapping the lightemitting element 20” refers to the size in the Y direction of the partof the first wiring portion 12 where the light emitting element 20overlaps. In the case where the wiring extending portion extends in theY direction (see FIG. 7A), the “width of the wiring extending portion”refers to the size of the wiring extending portion in the X directionand the “width of the part of the first wiring portion 12 overlappingthe light emitting element 20” refers to the size in the X direction ofthe part of the first wiring portion 12 where the light emitting element20 overlaps. The wiring extending portion 123 may extend to an outeredge of the base member 11 as seen in a front view, or an end of thewiring extending portion 123 may be apart from the outer edge of thebase member 11 as seen in a front view. In the case where, as seen in afront view, the wiring extending portion 123 is formed to extend in anX+ direction and/or an X− direction from the position where the lightemitting element 20 is to be placed, the light emitting element 20 maybe placed on the substrate 10 by using the wiring extending portion 123as a mark. This makes it easy to place the light emitting element 20 onthe substrate 10. The X+ direction is defined as a direction from leftto right on an X axis as seen in a front view, whereas the X− directionis defined as a direction opposite to the X+ direction.

The first wiring portions 12 may each include one wiring extendingportion 123 or a plurality of wiring extending portions 123 or no wiringextending portion 123. In the case where the first wiring portions 12includes the plurality of wiring extending portions 123, it ispreferable that the wiring extending portions 123 are located on both oftwo sides of the light emitting element 20 in the X direction. Thisallows the light emitting element 20 to be placed by using the wiringextending portions 123 located on both of the two sides of the lightemitting element 20 as marks, and thus can improve the positionalprecision at which the light emitting element 20 is placed on thesubstrate 10. In the case where a light-transmissive member is placed onthe light emitting element 20, the wiring extending portion may beformed to extend from the position where the light-transmissive memberis placed as seen in a plan view. With such a structure, thelight-transmissive member can be placed on the light emitting element 20by using the wiring extending portion as a mark. This makes it easy toplace the light-transmissive member on the light emitting element 20.

In the case where the first wiring portion 12 does not include thewiring extending portion 123 extending in the X direction, the contactarea size of the base member 11 and a reflective member (e.g., the firstreflective member 40) in the X direction can be increased. This canincrease the joining strength between the base member 11 and thereflective member (e.g., the first reflective member 40). Moreover, inthe case where the first wiring portion 12 does not include the wiringextending portion 123 extending in the X direction, the conductivebonding member 60 is less likely to spread in a wet state onto thewiring extending portion extending in the X direction. This can decreasethe area size in which the conductive bonding member 60 spreads in a wetstate, and thus the shape of the conductive bonding member 60 can beeasily controlled.

As shown in FIG. 7A, the first wiring portion 12 may include the wiringextending portion extending in the Y direction. Alternatively, as shownin FIG. 7B, the first wiring portion 12 does not need to include thewiring extending portion extending in the Y direction. In the case wherethe first wiring portion 12 includes the wiring extending portionextending in the Y direction, the light emitting element 20 may beplaced on the substrate 10 by using the wiring extending portion as amark. This can improve the positional precision at which the lightemitting element 20 is placed on the substrate 10. In the case where thefirst wiring portion 12 does not include the wiring extending portionextending in the Y direction, the contact area size of the base member11 and the reflective member (e.g., the first reflective member 40) inthe Y direction can be increased. This can increase the joining strengthbetween the base member 11 and the first reflective member 40, forexample. In the case where the first wiring portion 12 does not includethe wiring extending portion extending in the Y direction, theconductive bonding member 60 is less likely to spread in a wet stateonto the wiring extending portion extending in the Y direction. This candecrease the area size in which the conductive bonding member 60 spreadsin a wet state, and thus the shape of the conductive bonding member 60can be easily controlled.

In the case where the wiring 12 does not include the wiring extendingportion extending in the Y direction, it is preferred that length L2(see, FIG. 7B) of the first wiring portion 12 in the Y direction is inthe range of from at least 0.3 times to at most 0.9 times length L1 ofthe base member 11 in the Y direction. With the structure in which thelength L2 of the first wiring portion 12 in the Y direction is at least0.3 times the length L1 of the base member 11 in the Y direction, thearea size of the first wiring portion 12 is increased. This canfacilitate placement of the light emitting element 20. With thestructure in which the length L2 of the first wiring portion 12 in the Ydirection is at most 0.9 times the length L1 of the base member 11 inthe Y direction, the contact area size of the base member 11 and thefirst reflective member 40 can be increased. With the structure in whichthe length L2 of the first wiring portion 12 in the Y direction is atmost 0.9 times the length L1 of the base member 11 in the Y direction,the area size in which the conductive bonding member 60 spreads in a wetstate on the first wiring portion 12 can be decreased. In the case wherethe first wiring portion 12 includes the wiring extending portionextending in the Y direction, it is preferable that the length of thefirst wiring portion 12 in the Y direction, excluding the wiringextending portion extending in the Y direction, is in the range of fromat least 0.3 times to at most 0.9 times the length of the base member 11in the Y direction.

The light emitting device 1000 may include a light-transmissive member30 covering the light emitting element 20. With the structure in whichthe light emitting element 20 is covered with the light-transmissivemember 30, the light emitting element 20 can be protected against anexternal stress. The light-transmissive member 30 may cover the lightemitting element 20 while the light guide member 50 is located betweenthe light-transmissive member 30 and the light emitting element 20. Thelight guide member 50 may be located only between the light extractionsurface 201 of the light emitting element 20 and the light-transmissivemember 30 to fix the light emitting element 20 and thelight-transmissive member 30 to each other. Alternatively, the lightguide member 50 may cover a region from the light extraction surface 201to one or more of the lateral surfaces 202 of the light emitting element20 to fix the light emitting element 20 and the light-transmissivemember 30 to each other. The light guide member 50 has a higher lighttransmittance to light from the light emitting element 20 compared to alight transmittance of the first reflective member 40. Therefore, withthe structure in which the light guide member 50 covers the lateralsurfaces 202 of the light emitting element 20, light emitted from thelateral surfaces 202 of the light emitting element 20 is easilyextracted to the outside of the light emitting device through the lightguide member 50. This can improve the light extraction efficiency of thelight emitting device.

In the case where the light emitting device 1000 includes thelight-transmissive member 30, it is preferable that lateral surfaces ofthe light-transmissive member 30 are covered with the first reflectivemember 40. With such a structure, the light emitting device has a highcontrast between a light emitting region and a non-light emittingregion, namely, has a highly clear border between the light emittingregion and the non-light emitting region.

The light-transmissive member 30 may include wavelength conversionparticles 32. The wavelength conversion particles 32 absorb at least apart of primary light emitted by the light emitting element 20 and emitsecondary light having a wavelength different from that of the primarylight. With the structure in which the light-transmissive member 30contains the wavelength conversion particles 32, the light emittingdevice 1000 can emit mixed color light, which is a mixture of a color ofthe primary light emitted by the light emitting element 20 and a colorof the secondary light emitted by the wavelength conversion particles32. In the case where, for example, a blue LED is employed for the lightemitting element 20 and a phosphor such as YAG is employed for thewavelength conversion particles 32, the light emitting device can outputwhite light obtained as a result of light mixture which comprises bluelight emitted by the blue LED and yellow light emitted by the phosphorexcited by the blue light.

The wavelength conversion particles 32 may be dispersed uniformly in thelight-transmissive member 30, or may be locally present in the vicinityof the light emitting element 20 rather than the vicinity of a topsurface of the light-transmissive member 30. In the case where thewavelength conversion particles 32 are locally present in the vicinityof the light emitting element 20 rather than the vicinity of the topsurface of the light-transmissive member 30, even if thelight-transmissive member 30 contains the wavelength conversionparticles, which are weak against moisture, a matrix 31 of thelight-transmissive member 30 serves as a protective layer. This canmitigate deterioration of the wavelength conversion particles 32. Asshown in FIG. 2A, the light-transmissive member 30 may include a layercontaining the wavelength conversion particles 32 and a layer 33containing substantially no wavelength conversion particle 32. In the Zdirection, the layer 33 containing substantially no wavelengthconversion particle 32 is located as an upper layer to the layercontaining the wavelength conversion particles 32. With such astructure, the layer 33 containing substantially no the wavelengthconversion particle 32 serves as a protective layer. This can mitigatedeterioration of the wavelength conversion particles 32. Examples of thewavelength conversion particles weak against moisture include amanganese-activated fluoride-based phosphor. The manganese-activatedfluoride-based phosphor emits light having a relatively narrow spectralline width, which is preferable from the point of view of colorreproducibility. The expression that “containing substantially nowavelength conversion particle” indicates that unavoidable contaminationwith the wavelength conversion particles is not eliminated. It ispreferable that a content of the wavelength conversion particles in thelayer 33 is 0.05% by weight or lower.

The first reflective member 40 covers the lateral surface 202 of thelight emitting element 20 and a front surface of the substrate 10.Because the first reflective member 40 covers the lateral surfaces 202of the light emitting element 20, light traveling in the X directionand/or the Y direction from the light emitting element 20 is reflectedby the first reflective member 40 to increase the amount of lighttraveling in the Z direction.

As shown in FIG. 5, it is preferable that a shorter lateral surface 405,extending in the shorter direction, of the first reflective member 40and a shorter lateral surface 105, extending in the shorter direction,of the substrate 10 are substantially flush with each other. With such astructure, the width of the light emitting device 1000 in the firstdirection (i.e., X direction) can be shortened. Thus, the size of thelight emitting device 1000 can be decreased.

As shown in FIG. 8, it is preferable that a longer lateral surface 403,extending in the longer direction, of the first reflective member 40 onthe bottom surface 113 side is inclined toward inside of the lightemitting device 1000 while extending in the Z direction. With such astructure, when the light emitting device 1000 is mounted on themounting substrate, the lateral surface 403 of the first reflectivemember 40 is less likely to be in contact with the mounting substrate.Therefore, the mounting orientation of the light emitting device 1000tends to be stable. It is preferable that a longer lateral surface 404,extending in the longer direction, of the first reflective member 40 onthe top surface 114 side is inclined toward inside of the light emittingdevice 1000 while extending in the Z direction. With such a structurethe lateral surface 404 of the first reflective member 40 is less likelyto be contact with a collet (i.e., suction hole), and thus the firstreflective member 40 is less likely to be damaged when the lightemitting device 1000 is sucked by the collet. As can be seen from theabove description, it is preferable that the longer lateral surface 403of the first reflective member 40 on the bottom surface 113 side, andthe longer lateral surface 404 of the first reflective member 40 on thetop surface 114 side, are inclined inward in the light emitting device1000 while extending from the rear surface 112 toward the front surface111 (while extending in the Z direction). The inclination angle θ of thefirst reflective member 40 may be appropriately selected. In terms ofease of providing the above-described effects and of the strength of thefirst reflective member 40, the inclination angle θ is preferably in therange of from 0.3 degrees to 3 degrees, more preferably in the range offrom 0.5 degrees to 2 degrees, and still more preferably in the range offrom 0.7 degrees to 1.5 degrees. It is preferable that a right lateralsurface and a left lateral surface of the light emitting device 1000have generally the same shape as each other. Such a structure candecrease the size of the light emitting device 1000.

Embodiment 2

Light emitting devices in embodiment 2 according to the presentdisclosure shown in FIG. 9A through FIG. 12K are different from thelight emitting device 1000 in embodiment 1 in the number of the lightemitting elements placed on the substrate 10, the number of the recessedportions 16 and the vias 15 formed in the base member 11 and whether atleast one insulating film 18 is included or not.

As shown in FIG. 10, a light emitting device 2000 includes a first lightemitting element 20A and a second light emitting element 20B. The firstlight emitting element 20A and the second light emitting element 20B mayhave the same emission peak wavelength as, or different emission peakwavelengths from, each other. In the case where the emission peakwavelength of the first light emitting element 20A and the emission peakwavelength of the second light emitting element 20B are different fromeach other, it is preferable that the emission peak wavelength of thefirst light emitting element 20A is in the range of 430 nm or longer andshorter than 490 nm (i.e., wavelength range of blue light), and that theemission peak wavelength of the second light emitting element 20B is inthe range of 490 nm or longer and 570 nm or shorter (i.e., wavelengthrange of green light). With such an arrangement, the light emittingdevice 2000 has an increased color rendering properties.

As shown in FIG. 10, the vias 15 are each in contact with the firstwiring portion 12, the second wiring portion 13 and the third wiringportion 14. Such a structure can improve heat dissipation of the lightemitting device 2000. One of the third wiring portion 14 located in oneof the recessed portions 16 may be in contact with one of the vias 15 orwith the plurality of vias 15. In the case where the third wiringportions 14 are in contact with the plurality of vias 15, heatdissipation of the light emitting device 2000 can be further improved.In the case where as shown in FIG. 11, one of the third wiring portions14 located in one of the recessed portions 16 is in contact with two ofthe vias 15, the two of the vias 15 may be located in a left-rightsymmetrical manner with respect to a center line 11C of the recessedportion 16, which is a line parallel to the second direction (i.e., Ydirection).

In the case where the light emitting device includes a plurality of thelight emitting elements (the first light emitting element 20A and thesecond light emitting element 20B), it is preferable that the pluralityof light emitting elements are arrayed in a line in the first direction(i.e., X direction). Such a structure can shorten the size of the lightemitting device 2000 in the second direction (i.e., Y direction), andthus can decrease the thickness of the light emitting device 2000.

As shown in FIG. 10, the first light emitting element 20A and the secondlight emitting element 20B may be covered with one light-transmissivemember 30. Alternatively, as in a light emitting device 2000A shown inFIG. 12A and FIG. 12B, the first light emitting element 20A, and thesecond light emitting element 20B may be covered with differentlight-transmissive members 30 from each other. In the case where thefirst light emitting element 20A, and the second light emitting element20B are covered with one light-transmissive member 30, thelight-transmissive member 30 becomes larger, which can improve the lightextraction efficiency of the light emitting device. In the case wherethe first light emitting element 20A, and the second light emittingelement 20B are covered with different light-transmissive members 30from each other, the first reflective member 40 can exist between suchtwo light-transmissive members 30. With such a structure, the lightemitting device has a highly clear border between a light emittingregion and a non-light emitting region.

As in a light emitting device 2000B shown in FIG. 12C, thelight-transmissive member 30 disposed on each of the light emittingelements may include a first wavelength conversion layer 31E facing thelight extraction surface of the light emitting element and a secondwavelength conversion layer 31F provided on the first wavelengthconversion layer 31E. The first wavelength conversion layer 31E containsa matrix 312E and first wavelength conversion particles 311E. The secondwavelength conversion layer 31F contains a matrix 312F and secondwavelength conversion particles 311F. It is preferable that light fromthe first wavelength conversion particles 311E excited by the lightemitting element has an emission peak wavelength shorter than anemission peak wavelength of light from the second wavelength conversionparticles 311F excited by the light emitting element. With the structurein which the emission peak wavelength of the light from the firstwavelength conversion particles 311E excited by the light emittingelement is shorter than the emission peak wavelength of the light fromthe second wavelength conversion particles 311F excited by the lightemitting element, the light from the first wavelength conversionparticles 311E excited by the light emitting element can excite thesecond wavelength conversion particles 311F. This can increase theamount of the light excited by the second wavelength conversionparticles 311F. Because the second wavelength conversion layer 31F islocated on the first wavelength conversion layer 31E, the light from thefirst wavelength conversion particles 311E excited by the light emittingelement easily exits toward the second wavelength conversion particles311F.

It is preferable that the emission peak wavelength of the light from thefirst wavelength conversion particles 311E excited by the light emittingelement is in the range of from 500 nm to 570 nm. It is preferable thatthe emission peak wavelength of the light from the second wavelengthconversion particles 311F excited by the light emitting element is inthe range of from 610 nm to 750 nm. With such an arrangement, the lightemitting device 2000B can have a high color rendering properties. Thefirst wavelength conversion particles 311E may be formed of, forexample, a β-SiAlON-based phosphor, and the second wavelength conversionparticles 311F may be formed of, for example, a phosphor ofmanganese-activated potassium fluorosilicate. In the case where aphosphor of manganese-activated potassium fluorosilicate is used for thesecond wavelength conversion particles 311F, it is especially preferablethat the light-transmissive member 30 includes the first wavelengthconversion layer 31E and the second wavelength conversion layer 31F. Thesecond wavelength conversion particles 311F, which are formed of amanganese-activated fluoride phosphor, easily causes brightnesssaturation. However, with the structure in which the first wavelengthconversion layer 31E is located between the second wavelength conversionlayer 31F and the light emitting element, the light from the lightemitting element is less likely to be excessively directed toward thesecond wavelength conversion particles 311F. This can mitigatedegradation of the second wavelength conversion particles 311F. In thecase where the first wavelength conversion particles 311E and the secondwavelength conversion particles 311F are contained in the samewavelength conversion layer, it is preferable that the second wavelengthconversion particles 311F are dispersed in the entirety of thewavelength conversion layer whereas the first wavelength conversionparticles 311E are locally present in the vicinity of the lightextraction surface of the light emitting element. For example, the firstwavelength conversion particles 311E and the second wavelengthconversion particles 311F may be located in a mixed state in thevicinity of the light extraction surface of the light emitting element,and substantially the only second wavelength conversion particles 311Fmay be located in the vicinity of the surface of the wavelengthconversion layer opposite to the light extraction surface of the lightemitting element. In the case where the second wavelength conversionparticles 311F are dispersed in the entirety of the wavelengthconversion layer whereas the first wavelength conversion particles 311Eare locally present in the vicinity of the light extraction surface ofthe light emitting element, most of the first wavelength conversionparticles 311E are located closer to the light extraction surface of thelight emitting element than the second wavelength conversion particles311F. Therefore, the light from the first wavelength conversionparticles 311E excited by the light emitting element tends to excite thesecond wavelength conversion particles 311F. This can increase theamount of the light exited by the second wavelength conversion particles311F. In the case where a phosphor of manganese-activated potassiumfluorosilicate is used for the second wavelength conversion particles311F, the first wavelength conversion particles 311E can mitigate thatthe light from the light emitting element excessively irradiates thesecond wavelength conversion particles 311F. This can mitigatedegradation of manganese-activated fluoride phosphor as the secondwavelength conversion particles 311F.

The light-transmissive member 30 may include one kind of wavelengthconversion particles emitting green light or a plurality kinds ofwavelength conversion particles emitting green light. Thelight-transmissive member 30 may include one kind of wavelengthconversion particles emitting red light or a plurality kinds ofwavelength conversion particles emitting red light. For example, thelight-transmissive member 30 may contain a CASN-based phosphor and aphosphor of manganese-activated potassium fluorosilicate (e.g.,K₂SiF₆:Mn) as the wavelength conversion particles which emit lighthaving an emission peak wavelength in the range of from 610 nm to 750 nmwhen excited by the light emitting element. In general, the CASN-basedphosphor has an afterglow time shorter than that of the phosphor ofmanganese-activated potassium fluorosilicate. The “afterglow time” is atime period required until the light emission of wavelength conversionparticles is stopped after irradiation of the wavelength conversionparticles with excitation light is stopped. In the case where thelight-transmissive member 30 contains the CASN-based phosphor and thephosphor of manganese-activated potassium fluorosilicate, the afterglowtime of the light-transmissive member 30 can be shorter than in the casewhere the light-transmissive member 30 contains substantially the onlyphosphor of manganese-activated potassium fluorosilicate. In general,manganese-activated potassium fluorosilicate has an emission peak of anarrower half width than that of the CASN-based phosphor. Therefore, thephosphor of manganese-activated potassium fluorosilicate has a highercolor purity than the CASN-based phosphor, thereby realizing a highercolor reproducibility than the CASN-based phosphor. In the case wherethe light-transmissive member 30 contains the CASN-based phosphor andthe phosphor of manganese-activated potassium fluorosilicate, the colorreproducibility of the light emitting device is higher than in the casewhere the light-transmissive member 30 contains only the CASN-basedphosphor.

The weight of the phosphor of manganese-activated potassiumfluorosilicate contained in the light-transmissive member 30 ispreferably, for example, in the range of from 0.5 times to 6 times theweight of the CASN-based phosphor, more preferably in the range of form1 time to 5 times, the weight of the CASN-based phosphor, and still morepreferably in the range of from 2 times to 4 times the weight of theCASN-based phosphor. A larger weight of the phosphor ofmanganese-activated potassium fluorosilicate can improve the colorreproducibility of the light emitting device. A larger weight of theCASN-based phosphor can shorten the afterglow time.

It is preferred that the wavelength conversion particles formed of thephosphor of manganese-activated potassium fluorosilicate have an averageparticle size in the range of from 5 μm to 30 μm. It is preferred thatthe wavelength conversion particles formed of the CASN-based phosphorhave an average particle size in the range of from 5 μm to 30 μm. Aplurality of kinds of the wavelength conversion particles may becontained in the light-transmissive member 30 at substantially evenconcentrations while having a shorter particle size on average.Accordingly, light from the light emitting element can be easilydiffused, and thus, the color non-uniformity of the light emittingdevice can be mitigated. The plurality of kinds of the wavelengthconversion particles may be contained in the light-transmissive member30 at substantially even concentrations while having a larger particlesize on average. This can make it easy to extract the light from thelight emitting element, and thus can improve the light extractionefficiency of the light emitting device.

The CASN-based phosphor and the phosphor of manganese-activatedpotassium fluorosilicate may be contained in the same wavelengthconversion layer of the light-transmissive member 30, or in the casewhere the light-transmissive member 30 includes a plurality ofwavelength conversion layers, may be contained in different wavelengthconversion layers. In the case where the phosphor of manganese-activatedpotassium fluorosilicate and the CASN-based phosphor are contained indifferent wavelength conversion layers from each other, it is preferablethat the wavelength conversion particles formed of whichever materialhaving a shorter emission peak wavelength is located closer to the lightemitting element. With such a structure, light from the wavelengthconversion particles having a shorter emission peak wavelength canexcite the wavelength conversion particles emitting light having alonger emission peak wavelength. In the case where, for example, thephosphor of manganese-activated potassium fluorosilicate has an emissionpeak wavelength of about 631 nm and the CASN-based phosphor has anemission peak wavelength of about 650 nm, it is preferable that thewavelength conversion particles formed of the phosphor ofmanganese-activated potassium fluorosilicate are located closer to thelight emitting element.

The light-transmissive member 30 may contain an SCASN-based phosphor anda phosphor of manganese-activated potassium. Even in the case where thelight-transmissive member 30 contains the SCASN-based phosphor, theafterglow time can be shortened. The light-transmissive member 30 maycontain a CASN-based phosphor, a phosphor of manganese-activatedpotassium fluorosilicate, and a β-SiAlON-based phosphor. With such astructure, the color reproducibility of the light emitting device can beimproved.

As shown in FIG. 12C, the light emitting device 2000B may include atleast one via 15A connected with the first wiring portion 12, the secondwiring portion 13 and the third wiring portion 14, and also at least onevia 15B connected with the first wiring portion 12 and the second wiringportion 13 but apart from the third wiring portion 14. As shown in FIG.12D, as seen in a rear view, the via 15A overlaps the second wiringportion 13 and the third wiring portion 14, whereas the via 15B overlapsthe second wiring portion 13 but does not overlap the third wiringportion 14.

As shown in FIG. 12C, the light guide member 50 does not need to coverthe lateral surfaces of the light-transmissive member 30. Alternatively,the light guide member 50 may cover the lateral surfaces of thelight-transmissive member 30. The light-transmissive member 30 mayinclude the first wavelength conversion layer 31E facing the lightextraction surface of the light emitting element, the second wavelengthconversion layer 31F located on the first wavelength conversion layer31E and the layer 33, which is provided on the second wavelengthconversion layer 31F and contains substantially no wavelength conversionparticle. In this case, as in a light emitting device 2000C shown inFIG. 12E, lateral surfaces of the first wavelength conversion layer 31Emay be covered with the light guide member 50, whereas lateral surfacesof the second wavelength conversion layer 31F and lateral surfaces ofthe layer 33 including substantially no wavelength conversion particlemay be exposed from the light guide member 50. As in a light emittingdevice 2000D shown in FIG. 12F, the lateral surfaces of the firstwavelength conversion layer 31E and the lateral surfaces of the secondwavelength conversion layer 31F may be covered with the light guidemember 50, whereas the lateral surfaces of the layer 33 containingsubstantially no wavelength conversion particle (also referred to as a“substantially wavelength conversion particle free layer”) may beexposed from the light guide member 50. Alternatively, as in a lightemitting device 2000E shown in FIG. 12G, the lateral surfaces of thefirst wavelength conversion layer 31E, the lateral surfaces of thesecond wavelength conversion layer 31F and the lateral surfaces of thelayer 33 containing substantially no wavelength conversion particle maybe covered with the light guide member 50. In the case where as shown inFIG. 12G, the lateral surface of the first wavelength conversion layer31E, the lateral surface of the second wavelength conversion layer 31Fand the lateral surface of the layer 33 substantially including nowavelength conversion particle are covered with the light guide member50, the light guide member 50 maybe exposed from the first reflectivemember 40 at a light emission surface side of the light emitting device2000E. With the structure in which at least at least one part of thelateral surfaces of the light-transmissive member 30 is covered with thelight guide member 50, the light extraction efficiency of the lightemitting device can be improved. In the case where as in a lightemitting device 2000F shown in FIG. 12H, the light-transmissive member30 has at least one concaved and convexed portion on the lateralsurfaces, the at least one concaved and convexed portion of the lateralsurfaces of the light-transmissive member 30 may be covered with thelight-transmissive member 50. With such a structure, the lightextraction efficiency of the light emitting device can be improved.

It is preferable that as in a light emitting device 2000G shown in FIG.12I, the substantially wavelength conversion particle free layer 33includes a layer 33A containing reflective particles (also referred toas a “reflective particle containing layer), and includes a layer 33Bcontaining substantially no reflective particle (also referred to as a“substantially reflective particle free layer”). With the structure inwhich the reflective particle containing layer 33A is located on orabove the first wavelength conversion layer 31E and/or the secondwavelength conversion layer 31F, the light from the light emittingelement is diffused in the light-transmissive member 30 by the lightreflective particle containing layer 33A. This can increase the amountof the light from the first wavelength conversion layer particles 311Eand/or the second wavelength conversion particles 311F excited by thelight from the light emitting element. With the structure in which thesubstantially reflective particle free layer 33B is located on thereflective particle containing layer 33A, the substantially reflectiveparticle free layer 33B can serve as a protective layer for thereflective particle containing layer 33A. Such a structure is preferablein the case where the top surface of the light-transmissive member 30 isground in order to, for example, decrease the thickness of the lightemitting device. A reason for this is that with such a structure, onlythe substantially reflective particle free layer 33B is ground.Accordingly, the layer reflective particle containing 33A can besubstantially avoided from being ground, the amount of the reflectiveparticles contained in the light-transmissive member 30 is less likelyto vary in region by region. In the case where the substantiallywavelength conversion particle free layer 33 includes only thereflective particle containing layer 33A, it is preferable that thereflective particles are locally present close to the light extractionsurface of the light emitting element. With such a structure, a matrixof the substantially wavelength conversion particle free layer 33 canserve as a protective layer. The reflective particles may be formed oftitanium oxide, zirconium oxide, aluminum oxide, silicon oxide or thelike. Titanium oxide, which has a high refractive index, is especiallypreferable for the reflective particles. A content of the reflectiveparticles in the substantially wavelength conversion particle free layer33 can be appropriately selected. From the point of view of the lightreflectance, the viscosity in a liquid state and the like, it ispreferred that the content of the reflective particles in the layer 33is, for example, in the range of from 0.05 wt. % to 0.1 wt. %.

In the case where as in a light emitting device 2000H shown in FIG. 12J,the light-transmissive member 30 contains the wavelength conversionparticles, the light emitting device 2000H may include a cover film 34covering the top surface of the light-transmissive member 30. The coverfilm 34 may be an aggregate of covering particles, which arenanoparticles. The cover film 34 may be formed of the coveringparticles, or may include the covering particles and a matrix formed ofa resin material. With a structure in which the cover film 34 has arefractive index different from that of an outermost surface area of thematrix in the light-transmissive member 30, the chromaticity of thelight emitted by the light emitting device can be corrected. The“outermost surface area of the matrix in the light-transmissive member30” refers to the matrix configuring an outermost layer at a surface ofthe light-transmissive member 30 opposite to the light extractionsurface of the light emitting element. In the case where, for example,the refractive index of the cover film 34 is higher than the refractiveindex of the outermost surface are of the matrix in thelight-transmissive member 30, the amount of a reflected light at aninterface between the cover film 34 and the air is larger than theamount of a reflected light at an interface between the air and the partof the matrix of the light-transmissive member 30 that is located at theoutermost surface. This can increase the amount of the reflected lightreturning into the light-transmissive member 30, and thus the wavelengthconversion particles can be excited more easily. Therefore, thechromaticity of the light emitted from the light emitting device can becorrected toward the longer wavelength side. By contrast, in the casewhere the refractive index of the cover film 34 is lower than therefractive index of the outermost surface area of the matrix in thelight-transmissive member 30, the amount of the reflected light at theinterface between the cover film 34 and the air is smaller than theamount of the reflected light at the interface between the air and theoutermost surface area of the light-transmissive member 30. This candecrease the amount of the reflected light returning into thelight-transmissive member 30, and thus the wavelength conversionparticles is less likely to be excited. Therefore, the chromaticity ofthe light emitted by the light emitting device can be corrected towardthe shorter wavelength side. In the case where, for example, theoutermost surface area of the matrix in the light-transmissive member 30is formed of a phenyl-based silicone resin, and the chromaticity of thelight emitted from the light emitting device is corrected toward thelonger wavelength side, the covering particles may be formed of titaniumoxide, aluminum oxide or the like. In the case where the outermostsurface area of the matrix in the light-transmissive member 30 is formedof a phenyl-based silicone resin and the chromaticity of the lightemitted by the light emitting device is corrected toward the shorterwavelength side, the covering particles may be formed of silicon oxideor the like. In the case where the light emitting device includes aplurality of the light-transmissive members, the top surface of one ofthe light-transmissive members may be covered with the cover film 34,whereas the top surface of another of the light-transmissive membersdoes not need to be covered with the cover film 34. Whether or not toform the cover film 34 covering the top surface of thelight-transmissive member 30 may be appropriately selected depending onthe degree of correction of the chromaticity of the light emitted fromthe light emitting device. In the case where the light emitting deviceincludes the plurality of light-transmissive members, the top surface ofone of the light-transmissive members may be covered with a cover filmhaving a refractive index higher than the refractive index of theoutermost surface area of the matrix in the light-transmissive members,whereas the top surface of another of the light-transmissive members maybe covered with a cover film having a refractive index lower than therefractive index of the outermost surface area of the matrix in thelight-transmissive member. The material of the cover film 34 coveringthe light-transmissive member 30 may be appropriately selected dependingon the degree of correction of the chromaticity of the light emittedfrom the light emitting device. The cover film 34 may be formed by aknown method such as potting with a dispenser, ink-jetting, spraying orthe like.

As in the substrate 10 shown in FIG. 12K, it is preferable that thefirst wiring portions 12 include at least one narrow portion having ashort length in the Y direction and at least one wide portion having along length in the Y direction as seen in a front view. Length D4 of thenarrow portion in the Y direction is shorter than length D5 of the wideportion in the Y direction. The narrow portion is located at a positionwhich is apart from the center of the via 15 in the X direction as seenin a front view, and at which the electrodes of the light emittingelement are located in the X direction. The wide portion is located atthe center of the via 15 as seen in a front view. With the structure inwhich at least one of the first wiring portions 12 includes the narrowportion, the area size in which the conductive bonding member 60,electrically connecting the electrodes of the light emitting element andthe first wiring portions 12 to each other, expands in a wet state isdecreased. This can facilitate control of the shape of the conductivebonding member 60. The first wiring portions 12 may each have a shape ofwhich at least one corner is rounded.

As shown in FIG. 10, the light guide member 50 may continuously cover alight extraction surface 201A of the first light emitting element 20A,at least one lateral surface 202A of the first light emitting element20A, a light extraction surface 201B of the second light emittingelement 20B, and at least one lateral surface 202B of the second lightemitting element 20B. With such a structure, the light from the firstlight emitting element 20A and/or the second light emitting element 20Bcan be extracted also at a position between the light extraction surface201A of the first light emitting element 20A and the light extractionsurface 201B of the second light emitting element 20B. This can mitigatea luminance non-uniformity of the light emitting device. In the casewhere the emission peak wavelength of the first light emitting element20A and the emission peak wavelength of the second light emittingelement 20B are different from each other, the light from the firstlight emitting element 20A and the light from the second light emittingelement 20B can be mixed together in the light guide member 50. This canmitigate the color non-uniformity of the light emitting device.

The light emitting device 2000 may include the insulating film 18covering a part of the second wiring portion 13 (see, e.g., FIG. 9B).The provision of the insulating film 18 can ensure that a rear surfaceof the light emitting device is insulated and reduce a risk ofshort-circuit of the light emitting device. The insulating film 18 canalso reduce a risk that the second wiring portion from being delaminatedfrom the base member.

Embodiment 3

A light emitting devices in embodiment 3 according to the presentdisclosure shown in FIG. 13A, through FIG. 18B are different from thelight emitting devices in embodiment 2 in the number of the lightemitting elements placed on the substrate 10, the number of the recessedportions 16 and the vias 15 included in the base member 11, the shape ofthe base member 11, the shape of the recessed portions 16, the structureof the light-transmissive member 30, and whether a second reflectivemember 41 and a third reflective member 42 are included or not.

As shown in FIG. 14A, the vias 15 are each in contact with the firstwiring portion 12, the second wiring portion 13 and the third wiringportion 14. Such a structure can improve the level of heat dissipationof the light emitting device 3000. The number of the recessed portions16 and the vias 15 formed in the base member 11 may be appropriatelychanged depending on, for example, the size of the substrate 10.

As shown in FIG. 14A, the base member 11 may have at least one depressedportion MA in the front surface 111, in which the first reflectivemember is to be supplied. With the depressed portion 111A formed in thebase member 11, the contact area size of the first reflective member 40and the base member 11 is increased. This can increase the joiningstrength between the first reflective member 40 and the base member 11.It is preferable that two of the depressed portions 111A arerespectively located at both of two ends of the front surface 111 in thelonger direction (i.e., X direction). Such a structure can increase thejoining strength between the first reflective member 40 and the basemember 11 at both of the two ends of the base member 11. Therefore, thefirst reflective member 40 is less likely to be separated from the basemember 11.

As shown in FIG. 15 and FIG. 16, the substrate 10 may have at least onecentral recessed portion 16A opened on the rear surface 112 and thebottom surface 113 and apart from the lateral surface 105 of the basemember 11, and at least one end recessed portion 16B opened on the rearsurface 112, the bottom surface 113 and at least one of the lateralsurfaces 105 of the base member 11. The lateral surfaces 105 of the basemember 11 are located between the front surface 111 and the rear surface112 of the base member 11. With the structure in which the substrate 10has the end recessed portion 16B, the joining strength between the lightemitting device 3000 and the mounting substrate can be increased at bothof two ends of the light emitting device 3000. In the case where thesubstrate 10 includes a plurality of the end recessed portions 16B, itis preferable that the end recessed portions 16B are located at both oftwo ends of the base member 11 as seen in a rear view. Such a structurecan increase the joining strength between the light emitting device 3000and the mounting substrate. The substrate 10 may include either one ofthe central recessed portion 16A and the end recessed portion 16B. Inthis specification, the “recessed portion” refers to the centralrecessed portion 16A and/or the end recessed portion 16B. As shown inFIG. 15, the substrate 10 may have the plurality of vias 15, and theplurality of vias 15 may include a via 15 overlapping the centralrecessed portion 16A and/or a via 15 overlapping the end recessedportion 16B as seen in a rear view.

As shown in FIG. 14A, the light emitting device 3000 may include thefirst light emitting element 20A, the second light emitting element 20Band a third light emitting element 20C. The light emitting device mayinclude four or more light emitting elements. In this specification, the“light emitting element” refers to the first light emitting element 20A,the second light emitting element 20B and/or the third light emittingelement 20C. As shown in FIG. 17A, it is preferable that the first lightemitting element 20A, the second light emitting element 20B and thethird light emitting element 20C are arrayed in a line in the longerdirection (i.e., X direction) as seen in a front view. Such a structurecan decrease the thickness of the light emitting device 3000 in the Ydirection. In the case where the light extraction surface 201A of thefirst light emitting element 20A and the light extraction surface 201Bof the second light emitting element 20B are rectangular in shape, it ispreferable that a shorter side 2011A of the light extraction surface201A of the first light emitting element 20A and one shorter side 2011Bof the light extraction surface 201B of the second light emittingelement 20B face each other. In the case where the light extractionsurface 201B of the second light emitting element 20B and a lightextraction surface 201C of the third light emitting element 20C arerectangular in shape, it is preferable that the other shorter side 2012Bof the light extraction surface 201B of the second light emittingelement 20B and a shorter side 2011C of the light extraction surface201C of the third light emitting element 20C face each other. Such astructure can decrease the thickness of the light emitting device 3000in the Y direction. In this specification, the term “rectangle” or“rectangular” refers to a quadrangle including two longer sides, twoshorter sides, and four right-angled corners. In this specification, the“right angle” includes tolerance in the range of about ±3 degrees from90 degrees.

The emission peak wavelength of the first light emitting element 20A,the emission peak wavelength of the second light emitting element 20B,and an emission peak wavelength of the third light emitting element 20Cmay be substantially the same as, or different from, each other. In thecase where the emission peak wavelengths of the first light emittingelement 20A, the second light emitting element 20B and the third lightemitting element 20C are different from each other, the light emittingdevice 3000 can have a high color rendering properties. In the casewhere the first light emitting element 20A, the second light emittingelement 20B and the third light emitting element 20C are arrayed in aline, the first light emitting element 20A and the third light emittingelement 20C may have substantially the same emission peak wavelength,whereas the second light emitting element 20B may have an emission peakwavelength different from an emission peak wavelength of the first lightemitting element 20A. With such a structure, for example, when theoutput of the first light emitting element 20A is insufficient, such aninsufficiency can be compensated for by the output of the third lightemitting element 20C. The second light emitting element 20B having anemission peak wavelength different from emission peak wavelengths ofboth of the first light emitting element 20A and the third lightemitting element 20C may be located between the first light emittingelement 20A and the third light emitting element 20C, so that the colorrendering properties of the light emitting device can be increased andthe color non-uniformity thereof can be reduced. In this specification,the expression that “the emission peak wavelength is the same” indicatesthat a tolerance of about ±10 nm is allowed. In the case where theemission peak wavelength of the first light emitting element 20A is inthe range of from 430 nm or longer and shorter than 490 nm (i.e.,wavelength range of blue light), it is preferable that the emission peakwavelength of the third light emitting element 20C is in the range of430 nm or longer and shorter than 490 nm. With such an arrangement,wavelength conversion particles having an excitation efficiency peak inthe range of 430 nm or longer and shorter than 490 nm may be selected,and thus the excitation efficiency of the wavelength conversionparticles can be improved.

As shown in FIG. 14A, the light extraction surface 201A of the firstlight emitting element 20A and the light extraction surface 201B of thesecond light emitting element 20B may have substantially the same heightas each other in the Z direction. Alternatively, the light extractionsurface 201A of the first light emitting element 20A and the lightextraction surface 201B of the second light emitting element 20B mayhave different heights from each other in the Z direction. For example,as in a light emitting device 3000A shown in FIG. 14B, the lightextraction surface 201A of the first light emitting element 20A may bepositioned higher than the light extraction surface 201B of the secondlight emitting element 20B in the Z direction. With the structure inwhich the light extraction surface 201A of the first light emittingelement 20A positioned higher than the light extraction surface 201B ofthe second light emitting element 20B in the Z direction, the light fromthe second light emitting element 20B can easily expand in the longerdirection (i.e., X direction). As in a light emitting device 3000B shownin FIG. 14C, the light extraction surface 201A of the first lightemitting element 20A may be higher than the light extraction surface201B of the second light emitting element 20B in the Z direction. Withthe structure in which the light extraction surface 201A of the firstlight emitting element 20A is higher than the light extraction surface201B of the second light emitting element 20B in the Z direction, thelight from the first light emitting element 20A can easily expand in thelonger direction (i.e., X direction).

As shown in FIG. 17A, the shorter side 2011A of the light extractionsurface 201A of the first light emitting element 20A and the shorterside 2011B of the light extraction surface 201B of the second lightemitting element 20B may have substantially the same length as, or havedifferent lengths from, each other. For example, as shown in FIG. 17B,the shorter side 2011A of the light extraction surface 201A of the firstlight emitting element 20A may be longer than the shorter side 2011B ofthe light extraction surface 201B of the second light emitting element20B. With such a structure, the light from the first light emittingelement 20A can easily expand in the longer direction (i.e., Xdirection). As shown in FIG. 17C, the shorter side 2011A of the lightextraction surface 201A of the first light emitting element 20A may beshorter than the shorter side 2011B of the light extraction surface 201Bof the second light emitting element 20B. With such a structure, thelight from the second light emitting element 20B can easily expand inthe longer direction (i.e., X direction).

As shown in FIG. 14A, the light-transmissive member 30 may include afirst light-transmissive layer 31A facing the light extraction surfaces201A, 201B and/or 201C of the light emitting elements 20A, 20B and/or20C, and a wavelength conversion layer 31B located on the firstlight-transmissive layer 31A. The first light-transmissive layer 31Aincludes a first matrix 312A and first diffusive particles 311A. Thewavelength conversion layer 31B includes a second matrix 312B and thewavelength conversion particles 32. With the structure in which thelight-transmissive member 30 includes the first light-transmissive layer31A facing the light extraction surfaces 201A, 201B and/or 201C of thelight emitting elements 20A, 20B and/or 20C, the light from the firstlight emitting element 20A, the second light emitting element 20B and/orthe third light emitting element 20C is diffused in the firstlight-transmissive layer 31A. Therefore, the light from the first lightemitting element 20A, the light from the second light emitting element20B and/or the light from the third light emitting element 20C are mixedtogether in the first light-transmissive layer 31A, and thus theluminance non-uniformity of the light emitting device can be decreased.In the case where the first light emitting element 20A, the second lightemitting element 20B and/or the third light emitting element 20C havedifferent emission peak wavelengths from each other, the light from thefirst light emitting element 20A, the light from the second lightemitting element 20B and/or the light from the third light emittingelement 20C are mixed together in the first light-transmissive layer31A. Therefore, the color non-uniformity of the light emitting device isreduced.

It is preferable that the first light-transmissive layer 31A containssubstantially no wavelength conversion particles. The wavelengthconversion particles absorb a part of the light from the light emittingelements 20A, 20B and/or 20C when being excited by the light from thelight emitting elements 20A, 20B and/or 20C. With the structure in whichthe first light-transmissive layer 31A is located between the wavelengthconversion layer 31B and the light extraction surfaces 201A, 201B and/or201C of the light emitting elements 20A, 20B and/or 20C, the light fromthe first light emitting element 20A, the light from the second lightemitting element 20B and/or the light from the third light emittingelement 20C are mixed together in the first light-transmissive member31A before being absorbed by the wavelength conversion particles. Thiscan mitigate a decline in the light extraction efficiency of the lightemitting device.

As shown in FIG. 14A, a second light-transmissive layer 31C may beprovided on the wavelength conversion layer 31B. The secondlight-transmissive layer 31C contains substantially no wavelengthconversion particle. The second light-transmissive layer 31C may containa matrix 312C and second diffusive particles 311C. With the structure inwhich the second light-transmissive layer 31C contains the seconddiffusive particles 311C, the light from the light emitting elements20A, 20B and/or 20C and the light from the wavelength conversionparticles 32 excited by the light emitting elements 20A, 20B and/or 20Care mixed together in the second light-transmissive layer 31C. This canreduce the color non-uniformity of the light emitting device. Forexample, the second diffusive particles 311C may be formed of a materialhaving a refractive index lower than a refractive index of the firstdiffusive particles 311A. With such an arrangement, the amount of lightdiffused by the second diffusive particles 311C is decreased, and thusthe light extraction efficiency of the light emitting device 3000 can beimproved. As an Example of such a refractive index relationship betweenthe first diffusive particles 311A and the second diffusive particles311C, the first diffusive particles 311A are formed of titanium oxideand the second diffusive particles 311C are formed of silicon oxide.

As shown in FIG. 14A, the light emitting device 3000 may include thesecond reflective member 41 covering the electrode formation surface203A of the first light emitting element 20A, the electrode formationsurface 203B of the second light emitting element 20B and/or anelectrode formation surface 203C of the third light emitting element20C. With the structure in which the light emitting device 3000 includesthe second reflective member 41, the light from the light emittingelements 20A, 20B and/or 20C is less likely to be absorbed into thesubstrate 10. As shown in FIG. 2A, FIG. 10 and FIG. 12B, the firstreflective member 40 may cover the electrode formation surfaces of thelight emitting elements. Such a structure can also mitigate the lightfrom the light emitting elements to be absorbed into the substrate 10.It is preferable that the second reflective member 41 includes at leastone inclining portion having a greater thickness in the Z direction asbeing farther from the light emitting elements. With the structure inwhich the second reflective member 41 includes the inclining portion,the light extraction efficiency of the light emitting device 3000 can beimproved.

As shown in FIG. 14A, the light emitting device 3000 may include a thirdreflective member 42 provided between the light guide member 50 and thefirst reflective member 40. The third reflective member 42 covers thelateral surfaces of the light emitting elements while the light guidemember 50 is located between the lateral surfaces of the light emittingelements and the third reflective member 42. The light guide member 50may be formed by potting or the like after the third reflective member42 is foiled, so that the shape of the light guide member 50 is lesslikely to be varied region by region.

A surface of the third reflective member 42 that faces thelight-transmissive member 30 is preferably flat. With such a structure,the light-transmissive member 30 can easily be formed after the thirdreflective member 42 is formed. In the case where the light emittingdevice 3000 includes the third reflective member 42, the firstreflective member 40 covers the lateral surfaces of the first lightemitting element 20A and the lateral surfaces of the second lightemitting element 20B while the third reflective member 42 and the lightguide member 50 are located between the lateral surfaces of the lightemitting elements 20A/20B and the first reflective member 40.

As shown in FIG. 18A, a light emitting device 3000C may include a covermember 31D covering the at least one light extraction surface of thelight emitting element. The cover member 31D may include diffusiveparticles 311D. In this case, the cover member 31D covering the lightextraction surface can reduce the amount of light traveling in the Zdirection from the light emitting element, and thus can increase theamount of light traveling in the X direction and/or the Y direction.This can diffuse the light from the light emitting element in the lightguide member 50, and thus can mitigate the color non-uniformity of thelight emitting device. The cover member 31D is located between the lightextraction surface of the light emitting element and the light guidemember 50. It is preferable that at least a part of the lateral surfacesof the light emitting element is exposed from the cover member 31D thatcontains the third diffusive particles 311D. Such a structure canmitigate a decrease in the amount of the light traveling in the Xdirection and/or the Y direction from the light emitting element. Thecover member 31D may cover the light extraction surfaces 201A, 201B and201C of the light emitting elements 20A, 20B and 20C. Alternatively, thecover member 31D may cover one or more of the light extraction surfaces201A, 201B and 201C of the light emitting elements 20A, 20B and 20C.

As in the light emitting device 3000C shown in FIG. 18A, the lightextraction surface of one light emitting element may be covered by onlyone cover member 31D. Alternatively, as in a light emitting device 3000Dshown in FIG. 18B, a plurality of the cover members 31D may each coverthe light extraction surface of one light emitting element. As shown inFIG. 18B, a part of the light extraction surface may be exposed from thecover members 31D, so that the light extraction efficiency of the lightemitting element 3000D can be improved.

The cover member 31D may contain wavelength conversion particles. Theprovision of at least one of the cover member 31D, which covers thelight extraction surface of the light emitting element and contains thewavelength conversion particles, can facilitate color adjustment of thelight emitting device. The wavelength conversion particles contained inthe cover member 31D may be formed of a material same as, or differentfrom, wavelength conversion particles of the wavelength conversionparticles included in the wavelength conversion layer. In the casewhere, for example, the emission peak wavelength of the light emittingelement is in the range of 490 nm or longer and 570 nm or shorter (i.e.,wavelength range of green light), the wavelength conversion particlesmay be formed of a CASN-based phosphor and/or an SCASN-based phosphor,which can be excited by light in the range of 490 nm or longer and 570nm or shorter. Alternatively, the wavelength conversion particles may beformed of a phosphor of (Sr, Ca)LiAl₃N₄:Eu.

Embodiment 4

A light emitting device 4000 in embodiment 4 according to the presentdisclosure shown in FIG. 19 is different from the light emitting device2000 in embodiment 2 in the structure of the light-transmissive member.

The light emitting device 4000 includes a first light-transmissivemember 30A covering the first light emitting element 20A and a secondlight-transmissive member 30B covering the second light emitting element20B. The first light-transmissive member 30A and the secondlight-transmissive member 30B are different from each other in the typeof material included therein and/or the content of the material. Forexample, the first light-transmissive member 30A and the secondlight-transmissive member 30B are different from each other in thematerial of the wavelength conversion particles included therein and/orthe content of the wavelength conversion particles. Such a structure canfacilitate color adjustment of the light emitting device 4000. As shownin FIG. 19, the first light-transmissive member 30A may containwavelength conversion particles, whereas the second light-transmissivemember 30B may contain substantially no wavelength conversion particle.Such a structure can improve the light extraction efficiency of thelight from the second light emitting element 20B. For example, the firstlight emitting element 20A may have an emission peak wavelength in therange of 430 nm or longer and shorter than 490 nm (i.e., wavelengthrange of blue light), the second light emitting element 20B may have anemission peak wavelength in the range of 490 nm or longer and 570 nm orshorter (i.e., wavelength range of green light), the firstlight-transmissive member 30A may contain wavelength conversionparticles emitting green light and/or wavelength conversion particlesemitting red light, and the second light-transmissive member 30B maycontain substantially no wavelength conversion particle. Neither thefirst light-transmissive member 30A nor the second light-transmissivemember 30B may contain substantially any wavelength conversion particle.The first light emitting element 20A and the second light emittingelement 20B may have the same emission peak wavelength as, or differentemission peak wavelengths from, each other.

Hereinafter, components of the light emitting device in embodimentsaccording to the present disclosure will be described.

Substrate 10

The substrate 10 is a component on which one or more of the lightemitting element are placed. The substrate 10 includes at least the basemember 11, at least one first wiring portion 12, at least one secondwiring portion 13, at least one third wiring portion 14, and at leastone via 15.

Base Member 11

The base member 11 may be formed of an insulating material such as aresin, a ceramic material, glass or the like. Examples of the resinincludes epoxy, bismaleimide triazine (BT), polyimide, and the like. Thebase member 11 may be formed of a fiberglass-reinforced plastic (e.g.,glass epoxy resin). Examples of the ceramic material include aluminumoxide, aluminum nitride, zirconium oxide, zirconium nitride, titaniumoxide, titanium nitride, a mixture thereof, and the like. Among thesematerials, it is preferable to use, especially, a material having acoefficient of linear thermal expansion close to a coefficient of linearthermal expansion of the light emitting element. The lower limit of thethickness of the base member 11 may be appropriate selected. From thepoint of view of the strength of the base member 11, the thickness ofthe base member 11 is preferably 0.05 mm or greater, and more preferably0.2 mm or greater. From the point of view of the thickness (i.e., depthin the Z direction) of the light emitting device, the thickness of thebase member 11 is preferably 0.5 mm or less, and more preferably 0.4 mmor less.

First Wiring Portion 12, Second Wiring Portion 13, Third Wiring Portion14

The first wiring portion is located on the front surface of thesubstrate, and is electrically connected with the light emittingelement. The second wiring portion is located on the rear surface of thesubstrate, and is electrically connected with the first wiring portionthrough the via. The third wiring portion covers the inner wall of therecessed portion (i.e., recessed portion 16), and is electricallyconnected with the second wiring portion. The first wiring portion, thesecond wiring portion and the third wiring portion may be formed ofcopper, iron, nickel, tungsten, chromium, aluminum, silver, gold,titanium, palladium, rhodium, or an alloy thereof. The first wiringportion, the second wiring portion and the third wiring portion may eachbe formed of a single layer or a plurality layers of any of theabove-listed metal materials and alloys. From the point of view of,especially, heat dissipation, it is preferable to use copper or a copperalloy. The first wiring portion and/or the second wiring portion may becovered with a surface layer of, for example, silver, platinum,aluminum, rhodium, gold or an alloy thereof, from the point of view of,for example, the wettability on the conductive bonding member and/or thelight reflectance.

Via 15

The via 15 is provided in a through-hole passing from the front surfacethrough the rear surface of the base member 11, and electricallyconnects the first wiring portion and the second wiring portion to eachother. The via 15 may include the fourth wiring 151 covering the innersurface of the through-hole in the base member and a filling member 152filling a space enclosed by the fourth wiring 151. The fourth wiring 151may be formed of a conductive material substantially the same as amaterial of the first wiring portion, the second wiring portion and thethird wiring portion. The filling member 152 may be formed of aconductive material or an insulating material.

Insulating Film 18

The insulating film 18 can ensure that the rear surface of the lightemitting device is insulated and reduce a risk of short-circuit of thelight emitting device. The insulating film may be formed of materialsthat can be used in the field. The insulating film may be formed of, forexample, a thermosetting resin, a thermoplastic resin or the like.

Light Emitting Element 20, 20A and 20B

The light emitting element may be a semiconductor element that itselfemits light by being supplied with a voltage. For the light emittingelement, a known semiconductor element formed of a nitride semiconductoror the like can be used. The light emitting element may be, for example,an LED chip. Typically, the light emitting element includes at least thesemiconductor layered body 23, and in many cases, further includes theelement substrate 24. It is preferable that the light emitting elementhas a quadrangular shape, specifically, a square shape or a rectangularshape longer in one direction, when seen in a plan view. Alternatively,the light emitting element may have other shape, for example, ahexagonal shape. In the case of the light emitting element havinghexagonal shape, the light emission efficiency can be improved. Lateralsurfaces of the light emitting element may be perpendicular to the topsurface, or inclined inward or outward with respect to the perpendicularline to the top surface. The light emitting element includes positiveand negative electrodes. The positive and negative electrodes may beformed of gold, silver, tin, platinum, rhodium, titanium, aluminum,tungsten, palladium, nickel or an alloy thereof. The emission peakwavelength of the light emitting element may be selected from a range ofan ultraviolet region to an infrared region depending on the type of thesemiconductor material or the mixed crystal compositions of materials.An preferable material for the semiconductor layered body may be anitride semiconductor, which can emit light having a short wavelengthcapable of exciting wavelength conversion particles at a highefficiency. The nitride semiconductor is generally expressed by generalformula In_(x)Al_(y)Ga_(1-x-y)N (0≤x, 0≤y, x+y≤1). The emission peakwavelength of the light emitting element is preferably 400 nm or longerand 530 nm or shorter, more preferably 420 nm or longer and 490 nm orshorter, and still more preferably 450 nm or longer and 475 nm orshorter, from the points of view of, for example, the light emissionefficiency, the excitation of the wavelength conversion particles, andcolor mixing relations with light emission of the wavelength conversionparticles. Other examples of usable semiconductor material include anInAlGaAs-based semiconductor, an InAlGaP-based semiconductor, zincsulfide, zinc selenide, silicon carbide and the like. The elementsubstrate of the light emitting element is generally a substrate forcrystal growth, from which a semiconductor crystal forming thesemiconductor layered layer may grow. Alternatively, the elementsubstrate may be a support substrate for supporting the semiconductorelement structure that has been separated from the substrate for crystalgrowth. The element substrate may be light-transmissive, so thatflip-chip mounting can easily be applicable and the light extractionefficiency can easily be improved. The element substrate may be asubstrate formed of a material comprising sapphire, gallium nitride,aluminum nitride, silicon, silicon carbide, gallium arsenide, galliumphosphide, indium phosphide, zinc sulfide, zinc oxide, zinc selenide,diamond or the like. Among these materials, sapphire is preferable. Thethickness of the element substrate may be appropriately selected, andis, for example, 0.02 mm or greater and 1 mm or less. From the point ofview of the strength of the element substrate and/or the thickness ofthe light emitting device, it is preferred that the thickness of theelement substrate is 0.05 mm or greater and 0.3 mm or less.

Light-Transmissive Member 30

The light-transmissive member is provided above the light emittingelement, and protects the light emitting element. The light-transmissivemember contains the matrix formed of at least a material among thematerials listed below. Although it is not absolutely necessary, thelight-transmissive member may include the wavelength conversionparticles. In the case where the matrix in the light-transmissive membercontains the wavelength conversion particles 32 described below, suchlight-transmissive member can also serve as a wavelength conversionlayer.

The light-transmissive member may include the first light-transmissivelayer, the wavelength conversion layer and the second light-transmissivelayer provided as layered structure. For example, each of those layerscontains the matrix as described below. The matrices of the layers maybe formed of the same material as, or different materials from, eachother. Example of the light-transmissive member include: a sintered bodyin which the wavelength conversion particles and, for example, aninorganic material such as alumina or the like; or a plate-like crystalof the wavelength conversion particles.

Matrix 31 of Light-Transmissive Member

The matrix 31 of the light-transmissive member may be formed of amaterial that is transmissive to light emitted by the light emittingelement. The term “light-transmissive” refers to having a lighttransmittance, at the emission peak wavelength of the light emittingelement, of preferably 60% or higher, more preferably 70% or higher, andstill more preferably 80% or higher. The matrix of thelight-transmissive member may be formed of a silicone resin, an epoxyresin, a phenol resin, a polycarbonate resin, an acrylic resin, or amodified resin thereof. Alternatively, the matrix of thelight-transmissive member may be formed of glass. Among these materials,a silicone resin and a modified silicone resin, which are highlyresistant against heat and light, are preferable. Examples of thesilicone resin include dimethyl silicone resin, phenyl-methyl siliconeresin, and diphenyl silicone resin. The light-transmissive member mayinclude a single layer formed of one of the above-listed matrixmaterials, or may include a stack of layers formed of two or more of theabove-listed matrix materials. In this specification, the term “modifiedresin” encompasses a hybrid resin. The “matrix of the light-transmissivemember” encompasses the matrices of the first light-transmissive layer,the wavelength conversion layer and the second light-transmissive layer.

The light-transmissive member may contain various types of diffusiveparticles incorporated into the matrix which is formed of any of theabove-listed resin materials or glass. The diffusive particles may beformed of silicon oxide, aluminum oxide, zirconium oxide, zinc oxide orthe like. The diffusive particles may be formed of one material or acombination of two or more materials among these materials. Siliconoxide, which has a small coefficient of thermal expansion, is especiallypreferable. The diffusive particles may be nanoparticles, so that thedegree of scattering of the light emitted by the light emitting elementis increased and thus the amount of the wavelength conversion particlesto be used can be decreased. The “nanoparticles” are particles having aparticle size of 1 nm or longer and 100 nm or shorter. In thisspecification, the “particle size” is defined by, for example, D₅₀.

Wavelength Conversion Particles 32

The wavelength conversion particles absorb at least a part of primarylight emitted by the light emitting element and emit secondary lighthaving a wavelength different from that of the primary light. Thewavelength conversion particles may be formed of one material or acombination of two or more materials among the examples shown below.

Examples of materials of the wavelength conversion particles emittinggreen light include a yttrium-aluminum-garnet-based phosphor (e.g., Y₃(Al, Ga)₅O₁₂:Ce), a lutetium-aluminum-garnet-based phosphor (e.g.,Lu₃(Al, Ga)₅O₁₂:Ce), a terbium-aluminum-garnet-based phosphor (e.g.,Tb₃(Al, Ga)₅O₁₂:Ce), a silicate-based phosphor (e.g., (Ba, Sr)₂SiO₄:Eu),a chlorosilicate-based phosphor (e.g., Ca₂Mg (SiO₄)₄Cl₂: Eu), aβ-SiAlON-based phosphor (e.g., Si_(6-z)Al_(z)O_(Z)N_(8-z):Eu (0<z<4.2)),an SGS-based phosphor (e.g., SrGa₂S₄:Eu), an alkaline earthaluminate-based phosphor (e.g., (Ba, Sr, Ca)Mg_(x)Al₁₀O_(16+z):Eu, Mn(0≤x≤1)), and the like. Examples of materials of the wavelengthconversion particles emitting yellow light include an α-SiAlON-basedphosphor (e.g., M_(z)(Si, Al)₁₂(O, N)₁₆ (0≤z≤2; M is Li, Mg, Ca, Y, or alanthanide element excluding La and Ce), and the like. Theabove-described examples of material of the wavelength conversionparticles emitting green light include a material usable for thewavelength conversion particles emitting yellow light. For example, theyttrium-aluminum-garnet-based phosphor may have a part of Y replacedwith Gd, so that the emission peak wavelength is shifted toward thelonger side so as to emit yellow light. The above-described examples ofmaterial of the wavelength conversion particles emitting yellow lightinclude a material usable for wavelength conversion particles emittingorange light. Examples of materials of the wavelength conversionparticles emitting red light include a nitrogen-containing calciumaluminosilicate (e.g., CASN or SCASN)-based phosphor (e.g., (Sr,Ca)AlSiN₃:Eu), and the like. Another example of material of thewavelength conversion particles emitting red light may be amanganese-activated fluoride-based phosphor (i.e., phosphor representedby general formula (I): A₂[M_(1-a)Mn_(a)F₆] (in general formula (I), “A”is at least one selected from the group consisting of K, Li, Na, Rb, Csand NH₄; “M” is at least one element selected from the group consistingof the group IV elements and the group XIV elements; and “a” fulfills0<a<0.2)). A representative example of the manganese-activatedfluoride-based phosphor is a phosphor of manganese-activated potassiumfluorosilicate (e.g., K₂SiF₆:Mn).

Reflective Member (First Reflective Member, Second Reflective Memberand/or Third Reflective Member

The “reflective member” refers to the first reflective member, thesecond reflective member and/or the third reflective member. From thepoint of view of the light extraction efficiency in the Z direction, thereflective member has a light reflectance, with respect to the emissionpeak wavelength of the light emitting element, of preferably 70% orhigher, more preferably 80% or higher, and still more preferably 90% orhigher. It is also beneficial that the reflective member is white.Therefore, it is preferable that the reflective member contains a whitepigment in the matrix. The reflective member is a liquid state beforebeing cured. The reflective member may be formed by transfer molding,injection molding, compressing molding, potting or the like. In the casewhere the light emitting device includes the first reflective member,the second reflective member and/or the third reflective member, forexample, the third reflective member may be formed by drawing whereasthe first reflective member and the second reflective member may beformed by potting.

Matrix of Reflective Member

The matrix of the reflective member may be formed of a resin, forexample, a silicone resin, an epoxy resin, a phenol resin, apolycarbonate resin, an acrylic resin or a modified resin thereof. Amongthese resins, a silicone resin and a modified silicone resin, which arehighly resistant against heat and light, are preferable. Examples of thesilicone resin include dimethyl silicone resin, phenyl-methyl siliconeresin, and diphenyl silicone resin.

White Pigment

The white pigment may be formed of a single material or a combination oftwo or more materials among titanium oxide, zinc oxide, magnesium oxide,magnesium carbonate, magnesium hydroxide, calcium carbonate, calciumhydroxide, calcium silicate, magnesium silicate, barium titanate, bariumsulfate, aluminum hydroxide, aluminum oxide, zirconium oxide, andsilicon oxide. The white pigment may have any appropriate shape, and maybe irregular or crushed shape. It is preferable that the white pigmentis spherical from the point of view of the fluidity. The white pigmentmay have a particle size of, for example, in the range of about 0.1 μmor longer and about 0.5 μm or shorter. It is preferable that the whitepigment is as small as possible in order to improve the effects of lightreflection and covering. The content of the white pigment in thelight-reflective member may be of any appropriate value, and is, forexample, preferably in the range of 10 wt. % or higher and 80 wt. % orlower, more preferably in the range of 20 wt. % or higher and 70 wt. %or lower, and still more preferably in the range of 30 wt. % or higherand 60 wt. % or lower, from the points of view of the light reflectance,the viscosity in a liquid state, and the like. The unit “wt. %” refersto percent by weight, and represents the weight ratio of a material ofinterest with respect to the total weight of the reflective member,which is light-reflective.

Cover Member 31D

The cover member covers the light extraction surface of the lightemitting element. The cover member has functions of diffusing the lightfrom the light emitting element, or converting the light from the lightemitting element into light having an emission peak wavelength differentfrom that of the light from the light emitting element.

Matrix of Cover Member

The matrix of the cover member may be formed of a material the same asor similar to that of the matrix of the light-transmissive member.

Diffusive Particles of Cover Member

The diffusive particles of the cover member may be formed of a materialthe same as or similar to that of the diffusive particles of thelight-transmissive member.

Light Guide Member 50

The light guide member bonds the light emitting element and thelight-transmissive member to each other, and guides the light from thelight emitting element to the light-transmissive member. The matrix ofthe light guide member may be formed of a silicone resin, an epoxyresin, a phenol resin, a polycarbonate resin, an acrylic resin or amodified resin thereof. Among these resins, a silicone resin and amodified silicone resin, which are highly resistant against heat andlight, are preferable. Examples of the silicone resin include dimethylsilicone resin, phenyl-methyl silicone resin, and diphenyl siliconeresin. The matrix of the light guide member may contain a filler (e.g.,diffusive particles) and/or wavelength conversion particles the same asor similar to those in the above-described light-transmissive member.The light guide member may be absent.

Conductive Bonding Member 60

The conductive bonding member electrically connects the electrodes ofthe light emitting element and the first wiring portion to each other.The conductive bonding member may be formed of any one of bump foamed ofat least one material containing gold, silver, copper or the like; ametal paste containing metal powder of silver, gold, copper, platinum,aluminum, palladium or the like, and a resin binder; solder based ontin-bismuth, tin-copper, tin-silver, gold-tin or the like; and brazingmaterial of a low melting-point metal material; and the like.

A light emitting device in certain embodiment according to the presentdisclosure can be used for, for example, backlight devices of liquidcrystal display devices; various lighting devices; large-scale displays;various display devices for advertisements, destination guides and thelike; projector devices; and image reading devices for digital videocameras, facsimiles, copiers, scanners and the like.

While the present invention has been described with respect to exemplaryembodiments thereof, it will be apparent to those skilled in the artthat the disclosed invention may be modified in numerous ways and mayassume many embodiments other than those specifically described above.Accordingly, it is intended by the appended claims to cover allmodifications of the invention that fall within the true spirit andscope of the invention.

What is claimed is:
 1. A light emitting device, comprising: a substrate including: a base member including a front surface extending in a first direction as a longer direction and a second direction as a shorter direction, a rear surface located opposite to the front surface, a bottom surface adjacent to and perpendicular to the front surface, and a top surface located opposite to the bottom surface, and a first wiring portion located on the front surface, and a second wiring portion located on the rear surface; a first light emitting element electrically connected with the first wiring portion and placed on the first wiring portion; a second light emitting element disposed adjacent along the first direction to the first light emitting element; a first light-transmissive member including a first surface opposing to the first light emitting element and a second surface located opposite to the first surface; and a cover member including a third surface located farther away from the front surface of the base member than is the second surface in a third direction which is perpendicular to the first and second directions; wherein: the base member has a recessed portion opened on the rear surface and the bottom surface; the substrate includes a third wiring portion covering an inner wall of the recessed portion, and a via which runs through the base member from the front surface to the rear surface; and in the first direction, at least a portion of the cover member is located between the first light emitting element and the second light emitting element.
 2. The light emitting device of claim 1, wherein the cover member includes a fourth surface facing the second surface of the first light-transmissive member, the third surface being located opposite to the fourth surface.
 3. The light emitting device of claim 1, wherein the first light-transmissive member leaves a lateral surface of the first light emitting element uncovered.
 4. The light emitting device of claim 1, further comprising a second light-transmissive member including a fourth surface opposing to the second light emitting element and a fifth surface located opposite to the fourth surface, the second light-transmissive member being separated from the first light-transmissive member.
 5. The light emitting device of claim 4, wherein the third surface of the cover member is located farther away from the front surface of the base member than is the fifth surface of the second light-transmissive member in a third direction.
 6. The light emitting device of claim 5, wherein the first light-transmissive member leaves a lateral surface of the first light emitting element uncovered.
 7. The light emitting device of claim 6, wherein the recessed portion extends in the first direction, second direction and a third direction, a depth of the recessed portion defined in the third direction on a bottom point is larger than the depth of the recessed portion on an upper point, the bottom point and the upper point are on the rear surface and the bottom point and the upper point are on a line extending in the second direction, and the bottom point is closer to the bottom surface than the upper point.
 8. The light emitting device of claim 4, wherein the portion of the cover member is located between the first light-transmissive member and the second light-transmissive member in the first direction.
 9. The light emitting device of claim 1, wherein the recessed portion extends in the first direction, second direction and a third direction, a depth of the recessed portion defined in the third direction on a bottom point is larger than the depth of the recessed portion on an upper point, the bottom point and the upper point are on the rear surface and the bottom point and the upper point are on a line extending in the second direction, and the bottom point is closer to the bottom surface than the upper point.
 10. The light emitting device of claim 1, wherein the cover member contains a resin material.
 11. The light emitting device of claim 1, wherein the cover member covers the first light-transmissive member.
 12. The light emitting device of claim 1, wherein: the first light emitting element has a first lateral surface and the second light emitting element has a second lateral surface; and the light emitting device further comprising a reflective member covering the first lateral surface and the second lateral surface.
 13. The light emitting device of claim 12, wherein the cover member includes a portion covering the reflective member.
 14. The light emitting device of claim 13, wherein: the reflective member covers a lateral surface of the first light-transmissive member; and the recessed portion extends in the first direction, second direction and a third direction, a depth of the recessed portion defined in the third direction on a bottom point is larger than the depth of the recessed portion on an upper point, the bottom point and the upper point are on the rear surface and the bottom point and the upper point are on a line extending in the second direction, and the bottom point is closer to the bottom surface than the upper point.
 15. The light emitting device of claim 12, wherein the reflective member covers a lateral surface of the first light-transmissive member.
 16. The light emitting device of claim 12, wherein a lateral surface, extending in the shorter direction, of the reflective member and a lateral surface, extending in the shorter direction, of the substrate are substantially flush with each other.
 17. The light emitting device of claim 1, wherein the recessed portion has a maximum depth at a center of the recessed portion at the bottom surface.
 18. The light emitting device of claim 1, wherein the recessed portion has a maximum depth that is in a range of equal to or greater than 0.4 times and equal to or less than 0.9 times a thickness of the base member.
 19. The light emitting device of claim 1, wherein the base member has at least one additional recessed portion, and the recessed portion and the at least one additional recessed portion are located in a left-right symmetrical manner on the rear surface with respect to a center line of the base member, the center line being parallel to the second direction.
 20. The light emitting device of claim 1, wherein the via includes a fourth wiring and a filling member, and the filling member is formed of a material comprising a resin material. 